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By Carla Lupi, Alessandro Pescetelli

"Spent lead battery recycling still shows few weak points in the achievement of a 100% recycling of different waste matters and by- products arising from the recycling process. Some of said problems are dealing with aqueous streams outgoing the recycling plant, and more particularly, a) the waste waters discarded from the breaking and separation unit, b) purification of the spent electrolyte drained from waste batteries and upgrade to a quality compatible with full re-use by the batteries’ manufacturers, c) purification of the mother liquors discarded in the sodium sulfate crystallization process so to produce a salt of commercial grade. All of the above listed problems have been satisfactorily overcome applying an electrochemical process that, through different process conditions and parameters, is able to remove the harmful impurities that hinder the successful commercialization of such by products, or, at least, that can avoid heavy and expensive treatment plant and operation.IntroductionAlmost 100% of commercial lead and lead alloys produced by secondary lead plants is recycled to the new lead accumulators manufacture. The other by-products and residues produced through the lead recycling process may be classified into two groups:a) matters reusable in the new accumulators production processb) matters produced as a result of various reagents and additives used in the recycling process, to be sold to different market sectorsQuality and saleability of by-products are significant points for the economics of the secondary lead plant operation, because, if said by-products are not saleable, they are just wastes, so offsetting potential revenues, and, at the same time, adding a heavy burden to operating cost, like disposal cost [1]. When looking at a typical, modern lead scrap batteries recovery cycle, it is quite evident that we are still rather far from dealing with a waste-less technology (fig.1).The group a) includes 3 by-products produced through the breaking process: among those matters the polypropylene only usually reaches a standard quality suitable for sale to lead manufacturing sector or to other sectors as well. The other two by-products, electrolyte and separators, do not still reach, through a viable and effective regeneration process, a quality standard sufficient for their re-use in the lead batteries sector ."

Jan 1, 2008

By Kosei Morita, Osamu Nakano, Katsuhiko Nagai, Kazuhiro Mori

"The Sumitomo Toyo Smelter and Refinery commenced its operation in 1971 with three Peirce- Smith (PS) converters. “2 hot – 1 blowing” operation was practiced, that is one of two available converters was blowing and the other was standby in a hot state while the third converter was under repair. After several improvements, the stack time ratio reached around 90%; and processing 5 batches a day became possible.As a result of the expansion program of the Toyo smelter and refinery that started in 2001, the converter operation pattern was shifted from “2 hot – 1 blowing” to “2 hot – 2 blowing” with the installation of second converter blowers and an additional ladle crane.In 2005 a, the fourth converter was installed and “3 hot – 2 blowing” operation began. Also, with improvements experienced in the anode furnaces and the anode-casting wheel operation, today, the number of cycles has been increased up to more than 8.5 a day.The treatment techniques of fugitive gas containing sulfur dioxide from converter furnaces have been gradually reinforced, and the fixation rate of treated sulfur is currently being maintained at more than 99.9%. This paper introduces the operations described above, and the improvements in environmental management techniques for the Toyo PS converter operation."

Jan 1, 2009

By Murray Hughes, Neil Brown, John Carran

"A control system architecture has been developed using the Ward-Mellor structured analysis techniques for real-time applications. This approach has produced several advantages over traditional control system implementation methods including:•,partitioning of the control system into discrete control functions.•,easy identification of the interaction between individual control functions and the rest of the system including the impact of changes at the control system boundary (i.e. additional inputs or outputs).•,simplified control software testing.•,a closed loop design, implementation and documentation process.This paper describes a generic control application in which the process specification and control system design are logically linked. Both components are used by process engineers for on-going development.IntroductionAluminium is reduced from alumina in multiple electrochemical semi-batch reactors. Raw material additions and molten metal withdrawal are made at discrete intervals ranging from seconds to days. The electrolytic reduction process is continuous, despite the semi-batch nature of the material inputs and outputs. The chemical and physical processes that occur within each reactor are complex and interdependent, therefore simple methods used for the control of many chemical processes are impractical. The process control system is required to optimise operating efficiencies within the safe operating zone.The process control of aluminium reduction cells is heavily biased towards calculation of process variables with relatively few measured sensors. Each cell is controlled independently of the other cells, although changes to process conditions and raw material . quality will affect all cells. The process responds relatively slowly and with significant time lags. Measurements and process variable calculations occur each second, however the accuracy and precision of actuator response and sensor sampling are measured 111 milliseconds. Time-based scheduling is a significant component of reduction cell control."

Jan 1, 1994

By William C. Spindler

Five industrial installations of large lead-acid battery energy storage systems in operation in the United States, West Germany and the 'Republic of South Africa will be described. One example is for a deep mine shaft in which air ventilation and personnel evacuation require the highest reliability for emergency power. The battery system is designed for additional cost-effective benefits of peak load lopping and reactive power control. Commercially available lead-acid batteries of the following types are in use1 traction, truck, submarine, high power, and gel. Electrode grids of both the calcium and antimony alloy types are used. Applications include deep and shallow cycling as well as float and intermittent use. The advantages of sealed lead-acid batteries in UPS (uninterruptible power source) systems are well established throughout the world, and such system suppliers could readily develop markets for industrial emergency and peak power lead-acid storage battery installations.

Jan 1, 1990

By Hongfa Hu, Stavros A. Argyropoulos

"This paper describes a mathematical model which simulates numerically reaction driven fluid flow phenomena. The driving force of this reaction is an exothermic heat of mixing. In addition, the model predicts the heat and mass transfer phenomena where both heat source and heat sink co-exist in close proximity. The heat source is generated by an exothermic reaction. The heat sink is formed by a moving boundary such as the melting of a solid. This type of phenomena occur quite often in various metal processing operations in which exothermic additions are immersed in liquid metals. The model is based on the SIMPLER algorithm and uses an enthalpy method to predict the fluid flow, temperature, and concentration fields. The results indicate that the exothermic mixing reaction was responsible for an abrupt rise in temperature around the moving boundary. The intensity of this reaction was also found to be responsible for the enhanced convection of fluid and the acceleration of the moving boundary. The modelling results were also verified by experimental work which included velocity and temperature measurements in a low temperature physical model. IntroductionAlloying additions are used extensively in the treatment of liquid metals during metallurgical processes. The alloying additions introduced into liquid metals can be classified into various classes, each of which follows its own route[l]. As a major group, the exothermic additions follow two different steps during their assimilation into liquid metals. In the first step, upon immersion, a metal shell solidifies around such additions, and then melts back. At this point, the second step commences. During this second step, due to the mixing of the addition with a liquid metal, an exothermic reaction occurs, which liberates large amounts of heat, resulting in an enhanced convection in the liquid metal surrounding the addition."

Jan 1, 1994

By Peijia Lin

Wheat straw was chemically modified by alkaline treatment followed by succinylation and sodium carbonate treatment for the use of cadmium and nickel adsorbent. The adsorption efficiency was calculated in different conditions. The experimental parameters were solution pH, adsorbent dosage, contact time and initial metal concentrations. The biosorbent was analysed by FTIR (Fourier- Transform Infrared Spectroscopy) to investigate the changes of surface functional group. The maximum adsorption percentages of cadmium (>99%) and nickel (>98%) were achieved using 5 g/L adsorbent with 50 mg/L initial metal concentrations. The adsorption kinetic study showed that the reaction was pseudo-second order kinetics and the adsorption isotherm was well fit by the Langmuir adsorption model. The dynamic column study indicates that modified adsorbent has a better adsorption capacity towards cadmium than nickel.

By Hiroyuki. Fukuyama

The pseudo-binary phase diagram of the cuspidine (3CaO2?SiO2?CaF2) - CaF2 system has been studied by electron probe microanalysis (EPMA) and X-ray diffractometry (XRD). To prevent fluorine loss in the form of a HF gas by a reaction of CaF2 with water vapor at elevated temperatures, the equilibrium experiments were conducted with the sample hermetically sealed in a platinum tube. By employing this technique, it was successfully revealed that cuspidine exists as a stable phase and congruently melts at 1684 ± 1 K, and the cuspidine - CaF2 system presents a simple eutectic type of phase diagram, of which eutectic temperature has been estimated to be around 1540 K, corresponding to the composition of 40 mass% 3CaO?2SiO2 - 60 mass% CaF2?

Jan 1, 1999

By Patrick R. Taylor

Thermal plasma technology has a wide range of applications in extractive and process metallurgy. Beneficiation of complex ores, oxide reduction, melting/remelting of refractory metals and scrap, and the recovery of precious metals from waste products are some examples of potential uses for plasma technology. The highly concentrated enthalpy provided by plasma torches is a cleaner energy source and may give higher processing rates per reactor volume than conventional technologies. Some of the other advantages may be: controlled furnace atmosphere, ability to treat fine feed materials and rapid quenching. A review of some of the uses for plasma processing in non-ferrous process and extractive metallurgy is presented.

Jan 1, 1993

By Bruce W. Wessels

"Metal-organic chemical vapor deposition has been shown to be a highly versatile technique for the synthesis of complex oxides. High dielectric constant oxide thin films of SrTiO3, BaTiO3, Ba1-xSrxTiO3 and SrxBa1-xNb2O6 can be be be deposited at 800 ºC with this technique. The fluorine substituted B-diketonate precursors have been shown to be well-suited for the deposition of high quality, epitaxial thin films of these materials.IntroductionThere has been a resurgence of interest in thin film ferroelectric oxides as a result of the development of techniques to deposit high quality material. Both physical and chemical vapor deposition techniques have been realized. Of the chemical vapor deposition techniques, metal-organic chemical vapor deposition (MOCVD) has received the most interest for the deposition of ferroelectric oxide thin films. This results, in part, from the availability of a number of volatile metal-organic precursors.(l) Moreover, MOCVD offers the advantages of high growth rates, uniform coverage over large areas, conformability, abrupt interfaces and excellent epitaxial crystallinity. Of the metalorganic precursors, the B-diketonate complexes have played an important role especially in the deposition of ferroelectric oxides containing alkaline-earth metals such as BaTi03 and Ba1•XSrxTi03. For example, barium tetramethylheptanedionate Ba(thd)2 has been used in the preparation of BaTi03 by MOCVD.(2) These compounds, however, are not without their problems. Ba(dpm)2 has a relatively low volatility; and as a consequence, temperatures in excess of 180·C are required for volatilization. This leads to the necessity of a complex precursor delivery system to insure that the precursor does not condense before the reaction zone. Moreover, the Ba precursor tends to oligomerize leading to a decrease in vapor pressure as well as a problem with reproducibility. To counter these problems, novel liquid source and solid source precursor delivery systems have been developed. (3)(4)"

Jan 1, 1994

By A. Lackner

Using the CFD software package FIRE, the smelting process inside a cyclone reactor is modelled. The fluid flow is calculated 3 dim., using different turbulence models. The effects of design parameters (length and diameter of the cyclone, concentrate feeding tangentially or from the top,..) and operating conditions are investigated. Single particle traces illustrate how to increase particle retention time before the particles reach the liquid film flowing down the cyclone wall. Moreover a two phase flow approach is developed, based on the "Discrete Droplet Model". The position, velocity, diameter and temperature of each reacting particle is described. The results show the advantages of top concentrate feeding, large height/width ratio of the tuyeres and increasing number of tangentially gas inlets.

Jan 1, 1995

By Nozomu Hasegawa

The phase diagrams and microstructures of the slags in the Mitsubishi Continuous Copper Smelting and Converting Process were studied for the prevention of the magnetite troubles such as accretion build-up on furnace hearths and launders, blockages at the melt outlet, slag viscosity increases and so on. According to the results of those studies, the silica and lime contents in the silicate slag at the smelting furnace, and the lime content in the lime-ferrite slag at the converting furnace were changed, resulting in lower and more consistent copper levels in the discard slag, with much less need for operators to clean melt outlets and launders. However, these changes may decrease the desirable amount of accretion-coating inside the furnaces and thereby reduce furnace campaign lives. Therefore, a method of estimating the magnetite level in the melts was developed, and slag compositions and temperatures have been controlled within the appropriate ranges to prolong furnace lives and also prevent magnetite troubles.

Jan 1, 2003

By S. P. Song

A computational methodology based on the coupled finite element and boundary methods is developed to predict the free surface shapes of electrically conducting liquids supported by the electromagnetic field. The work is an extension of our previous FEIBE model for induction calculations. The free surface algorithm is developed using the Weighted Residual Method, the very same used for nonlinear finite element formulation. This allows the treatment of field computation and free surface prediction in the same manner, thus making easier the formulation of the magnetically-supported free surface problems. Like other nonlinear algorithms, the boundary/finite element free surface scheme is also iterative owing to the fact that free surface shapes are unknown a priori. But the numerical scheme is robust and efficient and is capable of handling rather complex free surface deformations. Computational algorithms will be given and are tested by comparing with other solutions whenever available. Computed results of magnetically-supported free surface shapes are presented for magnetic levitation under microgravity and floating zone refining processes under normal gravity.

Jan 1, 1996

By Bing Hu, Zhu-Cheng Huang, Guang-Bin Xia, Hu Peng, Hua Wang

"The temperature rising characteristics and reaction of the reduction of iron oxide pellets with anthracite fines were studied using a MW-L0316V microwave oven and Leica-DM-RXP polarizing microscope. The results show that iron oxide pellets and anthracite fines have good microwave absorbing properties, and high temperature and reducing atmosphere in a relatively short time for reduction of iron oxide pellets can be achieved. The reduction reaction, which follows the unreacted core model, is rapid and the metallization increases from 13.41% to 56.57% as the reduction end point temperature increases from 850oC to 950oC. The iron is formed, fine grain crystals of iron are transferred and the contraction of metal phase occurs firstly at the surface of pellets, which hinders the reduction reaction at the center of pellets. The rate of reduction reaction increases slowly as the reduction end point temperature increases from 950oC to 1050oC.IntroductionIron ore direct reduction can be divided into gas-based reduction and coal-based reduction. Owing to the effect of the resource and the related economic benefits [1, 2, 3, and 4], the development of gas-based direct reduction technology is restricted, but the development of coal-based direct reduction supported by the relevant industrial policy has very good prospects for application.As a source of clean energy, in China microwaves have been applied in many fields [5, 6, and 7]. Chen Jin studied the reduction of carbon pellets under microwaves, and has made some progress on reduction kinetics and reaction mechanisms. Other countries also have related research in this field [8 - 15], for example, Kotaro Ishizaki and Kazuhiro Nagata have done research on the reduction reaction of carbon magnetite heated by microwaves. The research shows that Fe3O4 is deoxidized to FeO at about 800oC, and FeO is deoxidized to Fe at 1000oC-1025oC. Due to the very good heat absorbing properties of iron oxide pellets and anthracite fines, the selective and rapid heating of microwaves can rapidly raise the temperature of pellets and anthracite, and the iron oxide pellets can be rapidly reduced. In order to provide enough theoretical basis for direct reduction by microwave heating, this paper studies the temperature rising characteristics, behavior of the reduction reaction and the changes of the iron oxide pellets and anthracite in the microwave field."

Jan 1, 2011

By V. M. Sokolov, Jr. DuPlessis

The technology for recycling fine wastes, grinding sludges or swarf, and solids such as slag that contain a high content of metallic material needed improving. The objective was to produce a master alloy that met the tight requirements of the Western manufacturers and achieve improved yields of the valuable elements, nickel and cobalt, to over 90%. The alloys from the production of Alnico. magnets were chosen for this work. A process is proposed .that is able to recycle all kinds of Alnico wastes. This process is able to reduce all detrimental elements, which are contained in the wastes, to within acceptable levels. Molybdenum, if present, is an exception. Depending on the levels of contamination of undesirable elements different recycling strategies are proposed. The majority of the wastes can be recycled by melting and refining with a liquid slag layer using unique melting furnaces that are relatively unknown in Western nations. The proposed technologies allow the reelamation of over 95% of the cobalt and nickel from any kind of Alnico waste, and there are no limitations on the proportion of different kinds of wastes in the charge. The proposed processes and technologies could also be applied to the recycling of grindings, turnin

Jan 1, 2000

By I. C. Knight

The current levels of copper smelter by-product acid production are reviewed on a regional basis, together with the possible changes in the future. There will be increasing pressure for all smelters to achieve a sulphur capture level of at least 95% by the end of the decade.

Jan 1, 1996

By James D. O, DeLa&apos

Multicomponent materials are common in nearly all areas of materials science and technology, yet the use of phase diagrams to represent these complex systems is hampered by the requirement of three or more dimensions for explicit graphical representation. In the present work, the "solid-modeling" capabilities of a computer aided design (CAD) system have been applied to the representation of three-dimensional phase diagrams. Relevant phase diagrams for a hypothetical quaternary eutectic system were constructed and used to demonstrate the capabilities of the technique. These capabilities lead to relative ease of phase diagram construction and improved access to qualitative and quantitative information. Results of this work are contrasted and compared to previous efforts toward computer ,representation of phase diagrams. It is concluded that solid-modeling of three-dimensional phase diagrams can be used to advantage in both education and research.

Jan 1, 1991

By G. Archer

ASARCO, a large and diverse producer of nonferrous metals, is involved primarily in the smelting and refining of lead and copper. Lead-antimony alloys, antimony trioxide, bismuth, cadmium oxide, selenium, tellurium, silver and gold are among products which result from processing by-products of smelting and refining. The complex mixture of concentrates at some smelters and the high impurity loads at some refineries result in various drosses, sludges, dusts and slags. In this paper, the complex interplant and intraplant transfer of by-products is addressed. These by-products result in an exchange of metals between the lead circuit and the copper circuit. Examples of the transfer of by-products and the prospects for the recycle of valuable products from wastes generated by customers and unrelated processors are also discussed.

Jan 1, 1992

By F. Michael Hosking

Modeling of a furnace brazing process is described. The computational tools predict the thermal response of loaded hardware in a hydrogen brazing furnace to programmed furnace profiles. Experiments were conducted to validate the model and resolve computational uncertainties. The results from selected furnace simulations and measured thermal events were compared. Critical boundary conditions that affect materials and processing response to the furnace environment were determined. "Global" and local issues (i.e., at the furnace/hardware and joint levels, respectively) are discussed. The ability to accurately simulate and control furnace conditions is examined.

Jan 1, 1998

By Sergio T. Amancio-Filho

FricRiveting technique is an alternative new spot joining process developed for thermoplastic-lightweight alloy structures. In this technique a cylindrical metallic rivet is used to join one or more thermoplastic / metal components by means of plasticizing and deforming the tip of the rotating rivet through frictional heating. Advantages of this new technique are e.g. short joining cycles, minimal sample preparation, absence of environmental emissions and enhanced mechanical performance in comparison to base materials. Qualitative and quantitative synchrotron X-Ray microtomographic and light optical microscopic analysis of a case-study joint on aircraft materials polyetherimide and aluminum 2024 showed that joint strength is mainly dependent on aspect ratio of the rivet (geometrical dependence) and quality of joint, (microstructural dependence), whereby increasing aspect ratios and lowering the percentage of defects usually yield improved strength.

Jan 1, 2009

By Jun Miao, Kang Liu, Jilai Xue, Jun Zhu

CO2 emissions must be reduced by at least 50 % by 2050, and hence the technical solutions to capture and convert CO2 into value–added products should be considered. A Cobalt(III) Schiff base complex (Salen–Co(III)) has been investigated as a catalyst for synthesis of cyclic carbonate from CO2 and epichlorohydrin(ECH) with tetrabutylammonium bromide (TBAB) as co–catalyst. To recover Salen–Co(III) for the next cycling operation, it was immobilized onto zeolite 13X through excessive impregnation method. The immobilized catalyst was characterized using XRD, SEM, BET and ICP–AES techniques. Catalytic tests showed that yield of cyclic carbonate reached 90 % using 0.5 mol % Salen–Co(III) at ambient conditions. The immobilized Salen–Co(III) exhibited better catalytic activity than the homogenous one when used at the first cycle, but the yield decreased by some 20 % after five cycles.

Jan 1, 2015